Elevator door safety device

ABSTRACT

Mechanical safety edges mounted on the leading edges of the elevator car doors are projected into the path of the hoistway doors during door closing to protect objects from being struck by either the car doors or hoistway doors. A toggle device restrains a harmonic motion mechanism from extending the safety edges when the doors are preopened as the car approaches a landing. The edges can be adapted for use in conjunction with radiant energy detecting devices.

United States Patent inventor Harry Berkovltz Glen Rock, NJ.

Appl. N 0. 26,229

Filed Apr. 7, 11970 Patented Dec. 14, 1971 Assignee Westinghouse Electric Corporation Pittsburgh, Pm.

ELEVATOR DOOR SAFETY DEVICE 12 Claims, ll Drawing Figs.

US. U 187/52,

l87/56, 49/27 lint. U B66b 13/00 Field oil rch 187/48, 51

[ 56] References Cited UNITED STATES PATENTS 2,791,654 S/l957 Nikazy 49/27 2,878,898 3/1959 Kraft 187/52 3,231,048 1/1966 Mitchell 187/51 Primary Examiner-Harvey C. Hornsby AttorneysA. T. Stratton, C. L. Freedman and Richard V.

Westerhotf ABSTRACT: Mechanical safety edges mounted on the leading edges of the elevator car doors are projected into the path of the hoistway doors during door closing to protect objects from being struck by either the car doors or hoistway doors. A toggle device restrains a harmonic motion mechanism from extending the safety edges when the doors are preopened as the car approaches a landing. The edges can be adapted for use in conjunction with radiant energy detecting devices H Patented Dec. 14, 1971 3 Sheets-Sheet 1 NQE HIP

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f M Q .I I 23 m 23 64 6 mmh m m INVENTOR Hurry Berkovdz WMM m ATTORNEY WITNESSES Patented Dec. 14, 1971 3 SheetsSheet 3 a; Ala-m? FIG. 6.

FIG. 7.

ELEVATOR IDOOR SAFETY DEVICE BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to a safety mechanisms for elevator doors and more particularly to devices for detecting the presence of an object in the path of the elevator doors.

2. Description of the Prior Art In the modern elevator installation, operation of the elevator car doom and the hoistway doors is controlled automatically. Conventionally, the master door operator on the car simultaneously operates both the car doors and the hoistway doors adjacent the car. Many forms of safety devices have been developed to protect passengers from being struck by the automatically operated doors.

The most widely used of these devices is the mechanical safety edge which is an elongated vane attached to the edge of the car door which is the leading edge during door closing. Relative movement between the vane and the car door when the vane comes into contact with an object in the path of the doors during door closing, operates a switch which is effective to stop or reverse the movement of the doors. Such a safety edge is disclosed in U.S. Pat. No. 2,878,898. Since the safety edge is only provided for the car door, and since the running clearance required for the car in the hoistway displaces the safety edge an appreciable distance from the hoistway doors, this type of device, as now utilized, does not offer optimum protection against being struck by the hoistway doors.

Usually means are provided to retract the safety edge without operating the switch which affects door operation as the doors reach the fully closed and the fully open position. A harmonic motion mechanism has been adopted by one manufacturer for this purpose. In the aforementioned patent, means are provided to maintain the safety edge retracted during door opening and until door closing is initiated.

Another type of safety device developed for use with eleva tor doors is the electrostatic detector. These devices project an electrostatic field in advance of the leading edge of the door. Changes in the capacitance to ground caused by an object in the path of the door are utilized to operate a switch in the door control circuits. Efforts have been directed towards shaping the field to encompass both the car doors and the hatch doors as in U.S. Pat. No. 3,370,677. U.S. Pat. No. 3,017,957 discloses the use of antennas on both sets of doors with various mechanical means for coupling the hoistway door antenna to the car. These electrostatic devices present problems of complexity, cost and maintenance.

Yet another type of protective device for elevator doors is the radiant energy detector. In the most commonly used radiant energy detector, a beam of visible light is projected across the entranceway to a photocell. Interruption of the beam by an object in the path of the doors is utilized to stop thedoors and for other control purposes such as altering the door open time. U.S. Pat. No. 2,785,771 discloses a scheme for projecting light beams along the paths of both the car doors and the hatchway doors. In another type of radiant energy detector disclosed in U.S. Pat. No. 3,367,450, an acoustic device mounted to the ceiling of the car justinside the doorway projects ultrasonic waves through the entrance and into the corridor adjacent the entrance. The detector is responsive only to ultrasonic waves reflected from moving objects.

Combinations of safety devices such as safety edges and visible light beam detectors are in wide spread use.

SUMMARY OF THEINVENTION A mechanical detector element carried on the edge of an elevator car door which is the leading edge during door closing is extended into the path of the hoistway doors to protect objects from being struck by the doors during door closing. The detector element, in the fonn of an elongated vane, is extended from the car door atan acute angle to the direction of movement to the door during door closing so that contact of the vane with an object, either in the path of the car door or the hoistway door, during door closing will be translated into relative movement between the vane and the car door. This relative movement can be utilized to operate a switch to stop or reverse the movement of the doors.

Extension of the detector vane during door opening is prevented to permit preopening of the doors as the car approaches a landing. In an exemplary embodiment of the invention, extension of the detector vane during door opening by a harmonic motion mechanism is restrained by a toggle device which is operated to its efiective condition by a cam mounted on the car as the door reaches the fully closed position. As the doors reach the fully open position, another cam mounted on the car trips the toggle to the inoperative position. The harmonic motion mechanism will maintain the detector vane in the retracted position until door closing is initiated. The upper and lower extremities of the detector vane are tapered to prevent damage to the vane should the car inadvertently move while it is extended.

The proposed safety edges can be used in conjunction with a light beam detector. In fact, the transmitter and receiver can be mounted in the detector vane itself. On center opening doors, the transmitter can be mounted in the detector vane on one door and the receiver in the detector vane on the other door, or both the transmitter and receiver can be mounted in one vane with a reflector in the other. Preferably, the components of the light detector can be connected to the trailing edge of the detector vane mountings with the beam passing through transparent portions of the vanes to orient the beam as near as possible to the middle of the opening between the car doors and the hoistway doors. This construction minimizes obstruction of the opening and lessens the problems of alignment.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference may be had to the exemplary embodiment shown in the accompanying drawings in which:

FIGS. la and lb are cross-sectional plan views of an elevator door installation embodying the invention;

FIG. 2 is a vertical sectional view of an elevator door installation embodying the invention taken through the doorway with the doors fully open;

FIG. 3a is an elevation view of the elevator car mechanism shown in FIG. I as seen from the hoistway;

FIGS. 3b, 3c, and 3d are fragmentary views of a portion of FIG. 30 for various phases of door operation;

FIG. 4 is an elevational view with parts broken away and parts in section of a detector element. constructed according to the invention;

FIG. 5 is a cross-sectional plan view of the detector element illustrated in H6. l taken along the line V-V;

FIGS. 6 and 7 are cross sectional plan views of the invention as adapted for use with light detectors.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIGS. 1, 2 and 3a show an elevator car l suspended by a cable 2 for movement in a hoistway 4 relative to a plurality of landings 6. The elevator car ll has a door opening 3 through which passengers enter and leave the elevator car. This door opening may be closed by doors in a conventional manner. For example, the doors may be singlespeed or two-speed and may be side-opening or center-opening doors. For present purposes, it will suffice to describe the invention as applied to doors of the single-speed, center-opening type. To this end, two center-opening doors 5 and A5 are illustrated in FIGS. 1 and 2. A number of similar components are employed for the doors 5 and A5. Insofar as is practicable, a component for the door A5 which is similar to a component for the door 5, will be identified by the same reference character employed for the component associated with the door 5, with the prefix A added.

The door 5 is provided with a door hanger 7 on which door hanger wheels 9 are mounted for rotation; The door hanger wheels for the two doors 5 and A5 are positioned for movement along a horizontally mounted track 11 in a conventional manner. The track 1 1 is secured to the elevator car 1.

Movement of the door 5 is effected by a lever 13 which is pivotally mounted on the elevator car 1 by means of a pin 15. The lower end of the lever 13 is pivotally connected to one end of a link 16, the other end of the link being pivotally connected to the door 5. By inspection of FIG. 3a, it will be observed that the lever 13 is coupled to the lever A13 by a link 17 which has its ends pivotally attached to the levers 13 and A13, respectively, by pivots 19 and A19. It will be observed that the pivot 19 is positioned above the pin 15, whereas the pivot A19 is located below the pin A15. Consequently, rotation of the lever 13 to open the door 5 moves the link 17 in the proper direction to open the door A5.

The lever 13 preferably is operated by a suitable door operator 21 which may include a reversible electric motor 23 coupled through suitable gearing to a shaft 25. The shaft 25 carries an arm 27 which is pivotally connected to one end of a link 29, the remaining end of the link 29 is pivotally connected to the lever 13. Consequently, the motor 23 may be energized in a conventional manner for the purpose of opening and closing the doors.

It is conventional practice to provide the hoistway in which the elevator car 1 operates with hoistway doors at each landing served by the elevator car which are similar to the doors 5 and A5 of the elevator car. For example in FIG. 2, the hoistway 31 in which the elevator car 1 operates is provided with an opening 33 for each landing served by the elevator car. Each of the openings is closed or exposed by hoistway doors similar to the doors employed for the elevator car. Thus doors 35 and A35 are provided which are similar to the doors 5 and A5 of the elevator car. The hoistway doors are mounted on hanger wheels 37 and A37 respectively which operate along a horizontal track 39 secured to the hoistway wall. When the elevator car is at a landing the hoistway door 35 is coupled through the car door 5 through the engagement of the bracket 36 by the vane 6 carried on the car door 5. In this manner, the hoistway doors are operated simultaneously with the car doors by the master door operator. The hoistway doors 35 and A35 are connected for synchronous movement through a conventional relating cable system.

In order to prevent the car doors or the hoistway doors from striking an object in the doorway during the door closing sequence, the car door 5 is provided with a mechanical detector unit 41. Referring to FIGS. 4 and 5 for a more detailed description, the detector unit 41 is composed of a U-shaped housing 43 which is connected to the leading edge of the car door 5 through a wedge shaped channel member 45. IN this manner, it can be seen that the detector unit can be easily removed from the door as a unit. It can be seen from FIG. 4 that the wedge shaped channel member 45 causes the axis of the U-shaped housing 43 to form an acute angle 0 with the plane of the car door. A hollow detector element, in the form of an elongated vane 47, is mounted for movement within the housing upon horizontal guide rods 49 and 51 by linear bearings 53 and 55. The detector vane is biased toward the extended position by leaf springs 57 and 59 connected to the top and bottom respectively of the base of the U-shaped housing 43. The stops 61 and 63, at the ends of guide rods 49 and 51 respectively, limit the extension of the detector vane 47. A vertical bar 65 is mounted on the guide rods between the linear bearings of the detector vane and the stops by linear bearings 67 and 69. Secured to the bar 65 is an angle bracket 71 which protrudes horizontally through slots 73 and 75 in the detector vane and the trailing leg 43B of the U-shaped mounting respectively. Secured to the bracket 71 by a clamp 77 is an actuating cable 79. The bar 65 is biased toward the stops 61 and 63 by leaf springs 81 and 83.

Reference to FIG. 4 will show that with no force applied to the actuating cable 79 the leaf springs will bias the bar 65 and the detector 47 to the right in FIG. 4 against the stops 61 and 63. Should pressure be applied to the leading edge of the detector vane 47 it will be moved to the left in FIG. 4 against the force of the leaf springs 57 and 59 while the leaf springs 81 and 83 maintain the bar 65 against the stops 61 and 63. The relative movement of the vane 47 with respect to the bar 65 will cause a finger 89 on the vane to deflect the actuating lever of a switch 91 carried by the bar 65. On the other hand, the application of the force drawing the actuating cable 79 to the left in FIG. 4, moving the bar 65 to the left, will cause the bar 65 to engage the flanges 85 and 87 on the vane 47 thereby drawing the vane 47 to the left with no accompanying actuation of the switch 91. It can be seen therefore, that pulling on the actuating cable 79 results in the retraction vane 47 into the housing 43 while release of the cable 79 pennits the vane to be extended.

Reference to FIGS. 1a and 1b shows that the retraction of the vane 47 provides running clearance between the car and the hoistway, while in the extended position the vane is projected into the path of the hoistway door 35. It will be seen from FIG. 1b that should the vane 47 strike an object during the door closing movement, the vane will stop while the continued movement of the door will cause relative movement between the vane and the bar 65 thereby actuating the switch 91. As mentioned previously, the switch 91 may be used to control a circuit which will stop or reverse the motion of the doors before the object is struck by the doors. The mass of the detector vane 47 is small, therefore, little impact force is imparted to the object touched by the safety edge. As is conventional with mechanical safety edges, the components of the systems should be adjusted so that the doors can be brought to a complete stop before they can strike the object.

in a conventional safety edge arrangement wherein the safety edge moves in a plane parallel to the plane of the car door, the area of protection afforded by the safety edge is limited to the thickness of the safety edge. it can be seen from FIG. 1b, however, that according to this invention a much broader area is protected since any object in the bracketed area 94, when touched by the detector vane 47, will translate the continued movement of the car door into relative movement between the vane 47 and the bar 65 therefore actuating the switch 91.

The actuating cable 79 is reeved around a pulley 93 horizontally mounted on a bracket 95 connected to the car door 5, and under a vertically oriented pulley 97 also connected to the car door. The other end of the cable 79 s connected to a point 99 near the circumference of a drum 101 rotatably mounted on the car door. A second cable 103 has one end connected to a groove in the rim of the drum 101 and the other end connected to a bracket 105 mounted on the floor of the car. The length of the cable 103 is such that when the car door is in the closed position as shown in FIG. 3a, the drum 101 is rotated counterclockwise thereby displacing the point 99 horizontally so that the actuating cable 79 will retract the detector vane against the springs tending to bias it to the extended position. It can be appreciated from FIG. 3 that as the door begins to open, the distance between the bracket 105 and the drum 101 is shortened so that the biasing force of the springs can rotate the drum 101 in the clockwise direction as the excess length of the cable 103 is wound around the rim of the drum 101. The bracket 105 is positioned on the floor of the elevator car relative to the drum 101 so that as the car door reaches the fully opened position, the drum 101 is again rotated in the counterclockwise direction as shown in FIG. 30 to again cause retraction of the safety edge. It is common practice to retract the safety edges when the car door is in the fully open position to maximize the door opening.

it can be appreciated from reference to FIG. 3 that as the doors begin to close, the horizontal component of the movement of the point 99 is large at first for a given rate of rotation of the drum 101 and approaches zero as the point 99 reaches the position shown in FIG. 3d at which the detector vane 47 is fully extended. Such a harmonic motion mechanism has been l0lOl4 0049 utilized for a number of years to extend and retract elevator door safety edges. The mechanism permits rapid extension of the safety edges both during door opening and door closing, but reduces the shock as the detector vane hits the stops by reducing the rate of movement to zero as the limits of travel are approached.

it is conventional to preopen the car doors on passenger elevators to expedite the transfer of passengers. Since according to this invention the detector vanes are extended into the path of the hoistway doors, it is necessary that safety edge extension be restrained during door opening to prevent them from being damaged or becoming jammed in the hoistway. To this end, the toggle W7 is provided which prevents rotation of the drum llfill during door opening, but does not interfere with the operation of the harmonic motion mechanism during door closing. The toggle device is composed of a toggle bar 109 pivotally mounted on a pin 111 attached to the car door. A spring 113 connected to the upper portion of the toggle bar and at the other end to a vertical bracket 115 extending downward from the pin 111 is operative to maintain the toggle bar in one overcenter position or the other. A roller 117 contacts a finger 11% connected to the innerface of the drum 101 when the doors are in the fully closed position. Another roller 11% cooperates with the cams 121 and 123 mounted on the floor of the elevator car at the limits of travel of the car door.

F168. 30 through 3d illustrate the position of the toggle device and the harmonic mechanism at various stages of door operation. As mentioned previously, the toggle 107 bears against the finger 1119 of the drum when the doors are in the closed position. As the doors begin to open as shown in FIG. 3b, the distance between the points of attachment of the cable 103 come closer together which would normally permit the drum lltill to rotate counterclockwise under the influence of the springs attached to the safety edge. However, the toggle 107 operating against the finger 119 maintains the detector vane in the retracted position since the force of the spring 113 is sufficient to overcome the force exerted by the springs in the detector vane. Since the cable 103 will slacken as the drum moves past the bracket 105, a spring 125 or other suitable talteup can be utilized to prevent the cable 103 from fouling. As the door approaches the fully open position illustrated in FIG. 3c, the roller 118 on the lower end of the toggle bar will come into contact with the cam123. Continued movement of the door will cause the toggle bar 109 to rotate counterclockwise until the spring 113 causes the toggle bar to snap over and maintain the position shown in FIG. 30 once the toggle bar has passed the vertical position. A stop on the bracket 113 prevents the toggle bar from overtraveling. Since the cable 103 will hold the drum in the counterclockwise position when the doors are fully open, the detector vane will remain retracted. During door closing however, as shown in FIG. 3d the harmonic motion mechanism will be effective to extend the safety edge into the path of the hoistway door. As the door reaches the fully closed position and the cable 103 rotates the drum to the position shown in FIG. 3a the roller 118 on the toggle will contact the cam 121 to reset the toggle to the posi tion shown in F16. 3a.

lFlGS. s and 7 illustrate adaptations of the invention for use with conventional light beam detectors. in the configuration shown in MG. s the mounting 15 on the door 5 is modified to accommodate a light beam projector and photocell combination 129. The mounting A45 on the opposing door A5 is also modified to accommodate a reflector 131. Transparent windows 127 and A127 are provided to permit the light beam to be projected from the projector receiver 129 across the door opening to the reflector 131 and thence back to the receiver 133. The presence of an object in the entranceway will prevent the reception of the beam by the receiver 129. This indication can be used as mentioned above for various control purposes. of course, alternatively, the receiver can be placed in one door mounting and the projector in the other.

FlG. ti also illustrates another light beam detector mounted in the detector vanes d7 and A47. A projector-receiver unit 133 similar to the unit 129 can be mounted inside the hollow vane -17 while the reflector 135 is placed inside the hollow vane A 17. The transparent windows 1137 and A137 permit the beam to be projected across the opening between the safety edges. The two light beam detector units can be used together or singly.

FIG. 7 shows another modification of the invention. in this configuration the transmitter receiver unit 133 is mounted directly to the leg 43b of the U-shaped mounting for vane 17. A slot in the vane 47 permits the vane to be extended and retracted. Similarly the reflector 133 is mounted to the leg A43 of the U-shaped mounting AM, and again a slot in the detector vane A47 permits extension and retraction. As in the previously described configuration, transparent windows 1137 and A137 are provided in the detector vane. This configuration presents fewer problems of alignment since the components are not carried by the movable vanes.

It will, therefore, be apparent that there has been disclosed a mechanically operated device which will protect objects from being struck by elevator hoistway and car doors. in view of the exemplary embodiments specifically disclosed, alternate configurations fully within the scope of the invention can be appreciated. For instance, instead of being mounted on horizontal guide rods, the vanes could be mounted for switch actuating rotation about a vertical axis when an object is encountered in the path of the doors. Also, in order to minimize the running clearance required for the car door, the U-shaped housing 43 for the vane could be pivotally mounted to the leading edge of the car door for rotation to the angle 0 when the safety edge is to be extended. As an alternative to this, the U-shaped housing could be recessed into a modified channel member 45 which protrudes unobtrusively into the cabin slightly as shown in FIG. 7 to maximize the useful car space.

I claim as my invention:

1. In an elevator system, a hoistway having a plurality of landings, horizontally sliding hoistway door means at a plurality of landings, an elevator car mounted for movement in the hoistway to serve the landings, horizontally sliding car door means for the elevator car, coupling means for coupling the car door means to the hoistway door means adjacent the position of the car, master door operator means for opening and closing the car door means and the hoistway door means adjacent the position of the car simultaneously, and a detector unit for detecting objects in the path of the door means, comprising a mechanical detector element, mounting means for mounting the mechanical detector element to the edge of the car door means which is the leading edge during door closing for movement therewith, and extension means for extending the mechanical detector element from the car door means ahead of and into the path of the hoistway door means, whereby objects in the path of the hoistway door means will contact the mechanical detector element in advance of the hoistway door means during door closing.

2. The combination of claim 1 wherein said mechanical detector element comprises an elongated detector vane extending over a substantial portion of said leading edge of said car door means and wherein the said mounting means includes means pennitting relative movement between the detector vane and said extension means, in combination with switch means operative from a first to a second condition in response to relative movement between said mechanical detector element and said extension means, whereby said switch is operated to said second condition when the mechanical detector element contacts an object in the path of said door means during door closing.

3. The combination of claim 2 wherein said mounting means includes guide means for directing movement of said detector vanes in the plane of said vane during relative movement between the detector vane and the said extension means, along a path forming an acute angle with the direction of movement of said door means during door closing, whereby continued movement of the car door in the closed direction when the detector vane cones into contact with an unyielding object disposed in the path of the door means will be translated into said relative movement between the detector vane and said extension means.

4. The combination of claim 3 wherein the leading edge of said detector vane is tapered rearward at the upper and lower extremities, whereby accidental movement of the elevator car when said detector vane is extended into the path of said hoistway door means will cause relative movement between said detector vane and said extension means as the detector vane comes into contact with the hoistway thereby preventing damage to said detector vane.

5. The combination of claim 3 in combination with radiant energy detector means operative to detect the presence of an object which interrupts a beam of radiant energy transmitted along the path traversed by the door means.

6. The combination of claim 5 including center opening car door means and hoistway door means, wherein the detector vane and means to extend said detector vane into the path of said hoistway door means is provided on the leading edge of each of said center opening car doors and wherein said radiant energy detector means includes a transmitter for transmitting a beam of radiant energy across the door opening and a receiver for receiving the beam transmitted across the door opening, said transmitter and receiver being mounted in the detector vanes.

7. The combination of claim 5 including center opening car door means and hoistway door means, wherein a detector vane and means for extending said vane into the path of said hoistway door means is provided on the leading edge of each of said center opening car doors, wherein said radiant energy detector means includes a transmitter for transmitting a beam of radiant energy across the door opening and a receiver for receiving the beam of radiant energy transmitted across the door opening, wherein said mounting means includes an elongated U-shaped housing mounted on a leading edge of each of said center opening car door means with the axis of said U- shaped housing forming said acute angle with the direction of door movement during door closing, wherein means are provided for securing to the trailing leg during door closing of the U-shaped housing said transmitter and receiver, and wherein said detector vanes include a portion in the line of sight of said beam of radiant energy which is transparent to said radiant energy.

8. The combination of claim 3 wherein the extension means includes yieldable means for biasing the detector vane to the extended position, a drum rotatably mounted on the car door, a first cable connecting the detector vane to a point on a face of the drum near the circumference, a second cable wound around the circumference of the drum and connected to a fixed point being vertically displaced from said drum and intermediate the limits of travel of said drum during door operation, and said second cable being of such a length that said drum is caused to rotate, drawing the point of attachment of the first cable to the drum, away from the leading edge of the car door thereby causing the detector vane to be retracted against the force of the yieldable means as the car door reaches both limits of travel.

9. The combination of claim 8 including control means for initiating the preopening of said car doors as the ear approaches a landing at which it is to stop, restraining means operative to prevent rotation of said drum during door opening, trip means for disengaging the retaining means when said doorsapproach the fully open position, and reset means for resetting the restraining means when the doors approach the fully closed position.

10. The combination of claim 9 wherein the restraining means includes a toggle device operable between a first position where it engages and prevents the rotation of said drum and a second position wherein it does not prevent rotation of said drum, and including means biasing the toggle to the operated condition, wherein said trip means comprises a cam mounted on the elevator car and eflective to operate said toggle from said first to said second condition as said car door approaches the fully open position and wherein said reset means comprises a cam mounted on the elevator car and effective to operate said toggle from said second condition to said first condition as the car door approaches the fully closed position.

11. The combination of claim 3 wherein said guide means comprises two horizontal guide rods with their axes aligned with said path forming an acute angle with the direction of movement of said door means during door closing, said detector vane being mounted for a horizontal movement along said guide rods and wherein said extension means includes yieldable means biasing said detector vane along said guide rods to the fully extended position, a vertical bar slidably mounted on said guide rods and operative to engage the detector vane to restrain the extension thereof by the yieldable means, an operating mechanism operative between a first condition wherein said vertical bar is drawn against said yieldable means to hold said vane in the retracted position and a second condition wherein said bar is permitted to follow the extension of said vane under the bias of the yieldable means, and a lost motion connection between the operating mechanism nd said vertical bar permitting relative movement between said bar and said vane should said'vane contact an object in the path of the doors.

12. The combination of claim 1 including control means for initiating the preopening of said car door means and said hoistway door means as the car approaches a landing at which it is to stop, and means within the extension means for preventing extension of said mechanical detector element from said car door means into the path of the hoistway door means during door opening. 

1. In an elevator system, a hoistway having a plurality of landings, horizontally sliding hoistway door means at a plurality of landings, an elevator car mounted for movement in the hoistway to serve the landings, horizontally sliding car door means for the elevator car, coupling means for coupling the car door means to the hoistway door means adjacent the position of the car, master door operator means for opening and closing the car door means and the hoistway door means adjacent the position of the car simultaneously, and a detector unit for detecting objects in the path of the door means, comprising a mechanical detector element, mounting means for mounting the mechanical detector element to the edge of the car door means which is the leading edge during door closing for movement therewith, and extension means for extending the mechanical detector element from the car door means ahead of and into the path of the hoistway door means, whereby objects in the path of the hoistway door means will contact the mechanical detector element in advance of the hoistway door means during door closing.
 2. The combination of claim 1 wherein said mechanical detector element comprises an elongated detector vane extending over a substantial portion of said leading edge of said car door means and wherein the said mounting means includes means permitting relative movement between the detector vane and said extension means, in combination with switch means operative from a first to a second condition in response to relative movement between said mechanical detector element and said extension means, whereby said switch is operated to said second condition when the mechanical detector element contacts an object in the path of said door means during door closing.
 3. The combination of claim 2 wherein said mounting means includes guide means for directing movement of said detector vanes in the plane of said vane during relative movement between the detector vane and the said extension means, along a path forming an acute angle with the direction of movement of said door means during door closing, whereby continued movement of the car door in the closed direction when the detector vane cones into contact with an unyielding object disposed in the path of the door means will be translated into said relative movement between the detector vane and said extension means.
 4. The combination of claim 3 wherein the leading edge of said detector vane is tapered rearward at the upper and lower extremities, whereby accidental movement of the elevator car when said detector vane is extended into the path of said hoistway door means will cause relative movement between said detector vane and said extension means as the detector vane comes into contact with the hoistway thereby preventing damage to said detector vane.
 5. The combination of claim 3 in combination with radiant energy detector means operative to detect the presence of an object which interrupts a beam of radiant energy transmitted along the path traversed by the door means.
 6. The combination of claim 5 including center opening car door means and hoistway door means, wherein the detector vane and means to extend said detector vane into the path of said hoistway door means is provided on the leading edge of each of said center opening car doors and wherein said radiant energy detector means includes a transmitter for transmitting a beam of radiant energy across the door opening and a receiver for receiving the beam transmitted across the door opening, said transmitter and receiver being mounted in the detector vanes.
 7. The combination of claim 5 including center opening car door means and hoistway door means, wherein a detector vane and means for extending said vane into the path of said hoistway door means is provided on the leAding edge of each of said center opening car doors, wherein said radiant energy detector means includes a transmitter for transmitting a beam of radiant energy across the door opening and a receiver for receiving the beam of radiant energy transmitted across the door opening, wherein said mounting means includes an elongated U-shaped housing mounted on a leading edge of each of said center opening car door means with the axis of said U-shaped housing forming said acute angle with the direction of door movement during door closing, wherein means are provided for securing to the trailing leg during door closing of the U-shaped housing said transmitter and receiver, and wherein said detector vanes include a portion in the line of sight of said beam of radiant energy which is transparent to said radiant energy.
 8. The combination of claim 3 wherein the extension means includes yieldable means for biasing the detector vane to the extended position, a drum rotatably mounted on the car door, a first cable connecting the detector vane to a point on a face of the drum near the circumference, a second cable wound around the circumference of the drum and connected to a fixed point being vertically displaced from said drum and intermediate the limits of travel of said drum during door operation, and said second cable being of such a length that said drum is caused to rotate, drawing the point of attachment of the first cable to the drum, away from the leading edge of the car door thereby causing the detector vane to be retracted against the force of the yieldable means as the car door reaches both limits of travel.
 9. The combination of claim 8 including control means for initiating the preopening of said car doors as the car approaches a landing at which it is to stop, restraining means operative to prevent rotation of said drum during door opening, trip means for disengaging the retaining means when said doors approach the fully open position, and reset means for resetting the restraining means when the doors approach the fully closed position.
 10. The combination of claim 9 wherein the restraining means includes a toggle device operable between a first position where it engages and prevents the rotation of said drum and a second position wherein it does not prevent rotation of said drum, and including means biasing the toggle to the operated condition, wherein said trip means comprises a cam mounted on the elevator car and effective to operate said toggle from said first to said second condition as said car door approaches the fully open position and wherein said reset means comprises a cam mounted on the elevator car and effective to operate said toggle from said second condition to said first condition as the car door approaches the fully closed position.
 11. The combination of claim 3 wherein said guide means comprises two horizontal guide rods with their axes aligned with said path forming an acute angle with the direction of movement of said door means during door closing, said detector vane being mounted for a horizontal movement along said guide rods and wherein said extension means includes yieldable means biasing said detector vane along said guide rods to the fully extended position, a vertical bar slidably mounted on said guide rods and operative to engage the detector vane to restrain the extension thereof by the yieldable means, an operating mechanism operative between a first condition wherein said vertical bar is drawn against said yieldable means to hold said vane in the retracted position and a second condition wherein said bar is permitted to follow the extension of said vane under the bias of the yieldable means, and a lost motion connection between the operating mechanism and said vertical bar permitting relative movement between said bar and said vane should said vane contact an object in the path of the doors.
 12. The combination of claim 1 including control means for initiating the preopening of said car door means and said hoistway door means as the car approaches a landing at which it is to stop, and means within the extension means for preventing extension of said mechanical detector element from said car door means into the path of the hoistway door means during door opening. 